Punch and die holder



United States Patent Office 3,477,329 PUNCH AND DIE HOLDER Gerard Gaston Fraus Smeets, Brampton, Ontario, Canada Filed Mar. 25, 1968, Ser. No. 727,117 Int. Cl. B26f 1/02 U.S. Ci. 83--685 1 Claim ABSTRACT OF THE DISCLOSURE The invention is directed to a sheet material punching unit in which the die is located in an anvil-like member having an extended foot portion for facilitating securing of the unit to a work table while the punch is supported by a C-type frame cantilevered from the anvil and immune to the effects of warpng or beuding of the extended foot portion.

Background of invention This invention relates to self-contained punching units and more particularly to composite punch and die holders adapted for seating on the bolster-plate of a punchpress in a position such that a punch held in the holder will be actuated by the stroke of the punch-press ram to pierce a workpiece overlying the die of the holder.

The invention is particularly concerned with the means for seating the self-contained punch and die holder on a work table which may not 'be a perfect plane surface but wherein punch and die alignment must be accurately maintained in spite of bolster-plate irregularities.

Self-contained punch and die holders are known in the art and a common one is the C-type as, for instance, shown in United States Patent 2,265,331-Wales. A further self-contained type is illustrated by United States Patent 3,130,620 Smeets.

The punch and die holders illustrated by the above mentioned United States patents sufier from a common defect in that if the press bolster-plate upon which they are mounted is not substantially flat the pressure of the mounting bolt as well as the pressure exerted during the punching stroke will cause twisting or beuding of the holder with the possible consequence of misalignment of the punch and die. In this instance a misalignment of of an inch is considered to be excessive. The punch must be substantially central of the die during the punching action.

It is the principal object of this invention to provide a self-contained punch and die holder unit which is substantially not subject to the misalignment disadvantages mentioned above when the holder is secured on a bolsterplate which is not substantially flat.

Summary of invention According to the present invention this defect may be over-come by providing that the base of the holder is divided into an anvil-like member which supports the die and a punch supporting arm and which merges with an extended lower member or mounting foot secured to the lower portion of the anvl-like member. Twisting of the mounting foot remote from the location at which the foot is secured to the anvil-like member does not produce any misalignment of the punch and die members.

Brief description of the drawings In order that the invention will be more clearly understood, reference will now be made to the figures of the drawing in which:

FIGURE 1 shows a punch and de holder of the prior art; i

FIGURE 2 shows a first embodiment of the nventon relating to a holder of the C-type; and

3,477,3 Z9 Patented Nov. ll, 1969 FIGURE 3 shows a further embodiment relating to a holder which resiliently supports the punch assembly.

Similar or equivalent parts of the three holders of the drawing are similarly designed.

Description of preferred embodiments Referring now to the prior art device of FIGURE 1, a self-contained C-type punch and die holder is shown having a base comprsed `by a die supporting portion 1 and an extending portion 2 which acts as a mounting foot and which is secured to the bolster-plate 8 by means of bolts 9. A die member 5 is accommodated in the portion 1 of the mounting foot 2. At the right-hand end of foot 2 a rising member 3 is integrally secured thereto and carries a further integral punch-supporting arm member 4 which extends over foot 2 to position a punch 6 and its stripping spring 7 in working position with respect to die 5.

If the bolster-plate 8 upon which the holder is mounted is substantially flat the misalignment of the punch and die will be produced only by the twisting of members 3 and 4 and will -be due to the relatively small pressure of the stripper spring 7 acting thereon during forced movement of the punch by the ram prior to actual piercing of the workpiece by the punch. This is usually of no consequence.

If the bolster-plate 8 is not substantially flat then a twisting or beuding movement, resulting from the pressure of the mounting bolts 9, will produce further misalignment of the punch and die prior to actual punching. The amount of misalignment may cause the resultant hole to be outside the limiting tolerances. This defect may be substantially eliminated according to the present invention by providing a foot as shown in FIG- URES 2 and 3 wherein the anvil-like portion of the mounting foot which holds the die 5 also directly supports in cantilever fashion, the members 3 and 4 which in turn support the punch assembly 6, 7.

Referring now to FIGURE 2, the anvil-like die supporting portion 1 of a foot member 2 has secured thereto in essence a C-type holder 3 extendng out in cantilever manner over foot member 2. The C-type holder portion 3 is essentially the same as shown in FIGURE 1. Mounting foot member 2, however, is only connected to member 3 through the medium of anvil-like portion 1 and, as a consequence of the construction, twisting and beuding of foot member 2 beyond portion 1 and due to securing bolt pressure and uneven bolster-plate surface is transmitted equally to die member 5, upper punch holding arm 4 and punch assembly 6, 7 to produce substantially no misalignment of the punch and die members. It will be realized that if the bolster-plate is not perfectly flat beneath portion 1 any misalignment caused by the twisting of this short piece of the mounting foot, i.e. that enclosed by the dottted lines and arrows, would be very minor and produce substantially no misalignment.

FIGURE 3 shows a modification of the self-contained holder wherein the upper support arm 4 is composed of a number of overlying resilient members which support the die 6 in the manner as described in United States Patent 3,130,620-Smeets. It should be realized that in all cases described a punch guide may be employed in conjunction With punch 6 and this will generally be the case.

It will be realized that serious misalignment caused by the prior art construction of C-type holders and other similar holders when 'bolted and used in conjunction with an uneven bolster-plate can now be substantially obviated by using a holder according to the present in- Vention.

What is claimed is:

1. A punch and die unit comprising an anvil-like die-accommodating member adapted to seat on the work table of a punch-press machine, an elognated foot portion attached to the lower part of the anvl-like member and extending substantially parallel to the bottom arm of a C-shaped member Secured at one end of its ends to the upper part of the anvil member in cantilever fashion, the other end of the C-shaped member ove'rlying the anvl-like member, said other end being provided with means to accommodate a punch member in aligned working relationshp with a die member supported in the anv'l member, and wherein the extended foot portion is provided with fastening means to secure said ber substantially does not affect the alignment of sup ported punch and die members.

References Cited UNITED STATES PATENTS JAMES M. MEISTER, Primary Examiner U.S. Cl. X.R.

unit to a work table so that bending of said foot mem- 83 698 

